Yarn clamp



Sept. 2, 1952 C, F, BROWN 2,608,845

YARN CLAMP Filed Oct. 11, 1951 Patented Sept. 2, 1952 Charles F. rown, PawtuckehR. I., assigner to Hemphill Company, Pawtucket,'R. I., a corporation of Massachusetts l Applicationctober 11, 1951, Serial No. 250,829

This invention relates to an improvement in yarn clamps for a circular, independent needle. knitting machine. Its object is to effectively prevent the overfeedng of yarn when a yarn lever is moved out cf action and until it goes into action again. v

When a yarn leverl of a circular, independent needle knitting machine is moved from an active to an inactive position, the yarn is guided by the needles and by the yarn lever into a binder and cutter. To insure this, the yarn should remain under tension. If there is slack in the yarn adjacent the needles at this time, the probability is that it will not be properly bound and cut. Such slack may occur as the result of the abruptness of the movement of the yarn lever, vibration, or other causes. Devices to overcome this difculty have taken the form of clamps of various types positioned as near to the needle circle as is conveniently practicable. Usually, such clamps are operated by the mechanism which operates the yarn levers. However, as a rule, they are inefficient because they do not become effective until the yarn lever approaches its inactive position, whereas they should operate as soon as possible after the yarn lever has left its feeding position and, in reverse, release the yarn too soon as the yarn lever returns to its feeding position. Furthermore, too much operating energy is required. This strains the yarn lever operating mechanism and, not infrequently, damages it.

The purpose of this invention is to provide a yarn clamp which is extremely simple and inexpensive and which is eiective to clamp the yarn almost immediately when the yarn lever starts to rise or otherwise move out of its feeding position.

One type of clamp of this invention, applied to a circular, independent needle knitting machine of the Banner type, is shown in the drawing, of which:

Figure 1 is a side elevation;

Figure 2 is Van end elevation;

Figure 3 is a detailed view corresponding to a part of Figure 1; and

Figure 4 is a view similar to Figure 3, showing a structural modification.

As shown in Figure 1, the machine is provided with yarn levers such as I, pivotally mounted in the usual way on an extension 2 of the carrier ring 3. Yarn lever I may be moved from its yarn feeding position to its inactive position (shown in dotted and dash line in Figure 1) by usual means (not shown). When such means operates to so move the yarn lever, lever 4 Claims. (Cl. (i6-145) 2 4 will be swung towards the `vertical b-y projection 5 of the yarn lever. Since lever 4 is held in contact with projection 5 f of Ythe yarn lever I by spring 6, it may be vused effectively to operate the yarn clamp of the type with which this invention is concerned. n

This clamp consists of a suitable plate 'I so mounted upon the ymachine as to overlie the upper end of lever 4. The underside of plate 'I adjacent the end which projects towards the cylinder of the machine' is provided with a transverse notch 8, the front' edge of which consists of a substantially vertical wall 9 and the rear edge of which is bevelled as shown at I0 in Figures 1, 3 and 4. Penetrating plate 'I and communicating with the bottom of notch 8 is a hole I I through which the yarn I2 is threaded. Consequently, yarn I2 passes through lnotch 3 on its way to the yarn lever.

Amxed by one end to the underside of plate 1, as at I3, is a light, concave-convex leaf spring I4. This spring is in alignment with lever 4 and. also, is so positioned that, when yarn lever I is in yarn feeding position and lever 4 is consequently in its forward position, as shown in Figure 1, the upper end of lever 4 will closely underlie spring I4 at a point in front of the bottom of the downward curve of the spring. As soon as yarn lever I is caused to leave its yarn feeding position, lever 4 will be swung towards the vertical with the result that its tip I5 will immediately engage spring I4 and force it upwardly so that the free end I6 of spring I4 will engage bevel I0 of notch 8 and will then move upwardly and forwardly along this bevel as the result of consequent reduction in the curvature of the spring until it strikes the lower corner of wall 9. Since yarn I2 passes between the end I6 of spring I4 and wall 9, it will be clamped securely very shortly after the movement of the yarn lever begins and any further motion of the yarn lever and, consequently, of lever 4, will tend to elongate spring I4 and thus add additional clamping force to the spring. See Figure 3.

When the yarn lever action is reversed and yarn lever I moves from its inactive to its yarn feeding position, the release of the yarn from the yarn clamp is delayed until the motion of the yarn lever is substantially completed. Thus, the yarn I2 remains taut and proper feeding to the needles is assured.

The forward end of spring I4 is preferably bent into a cylinder as shown but, of course, this shape may be altered to any other desired one Such a modification is shown in Figure LiV where forward wall 9 is shown as the rear edge i8, of a separate piece I1 attached to'plate 'in which has been made correspondingly thinner as at I9, to accommodate piece l?. This piece may be made of porcelain, for example, which f is the usual material for yarn guides and it may be replaceably axed to plate 1.

Another advantage of considerable importance gained by the use of this invention is that very little energy is required to cause lever il to operate spring I4. Present day yarn clamps, designed for equivalent usage, require the application of very considerable energy derived from the mechanism which operates the yarn levers` This has resulted too frequently in the bending of parts oi this mechanism.` f

I claim:

1. In a circular, independent needle, knitting machine, a yarn clamping mechanism comprising a clamping plate, a recess in said plate through which yarn may pass, a curved leaf spring attached to said plate in 'such a manner that when said spring is at rest it is spaced from the surface of said recess but is engageable therewith and thereafter, by a reduction in its curvature, it is adapted to clamp said yarn between said spring and a wall of said recess and means for forcing said spring into engagement with said recess and for elongating said spring by reducing its curvature.

2. A yarn clamping mechanism for a circular, independent needle, knitting machine having a yarn lever comprising a lever associated with said yarn lever, and a clamping plate having a recess in its surface, an aperture in said plate for admitting yarn to said recess, a curved leaf spring attached to said spiate and adapted to enter said recess and clamp said yarn when the curvature of said spring is reduced, said plate being so positioned that said lever reduces the curvature of said spring when the yarn lever is removed from its yarn feeding position.

3. A yarn clamping device comprising a clamp- Zfing plate having a recess in one surface thereof, Van aperture in said plate for admitting yarn Vto said recess, and a curved leaf spring adapted to enter said recess and clamp said yarn when the curvature of said spring is reduced.

4. A yarn clamping device having a clamping plate with a recess in one surface thereof through which yarn may pass, one side of said recess being substantially perpendicular to said surface, the opposite side of said recess sloping from said surface toward said perpendicular side, and a resilient yarn clamping member normally spaced from said sides of said recess and adapted to be moved into contact with said sloping side and said perpendicular side.

CHARLES BROWN.

REFERENCES CITED The following references are of record in the le of this patent:

UNTTED STATES PATENTS 

